This invention relates to the generation and encryption of communications, their transmission over a communications network, and the receipt and decryption of the messages sent; and, more particularly, to the creation and use of “one-time pads”, one-time keys, and the keys themselves, in support of key-based cryptographic techniques used for such purposes.
An expectation of communications network users is the privacy of their communications sent over the network. One way of achieving privacy is cryptographic protections afforded a user for any information and data they send. It has been found that most forms of encryption are vulnerable to discovery through the use of various techniques; for example, frequency analysis by which multiple communications employing the same coding scheme are analyzed to locate more commonly used letters of the alphabet, combinations of letters, words, etc. Using these techniques, almost any coding scheme is ultimately decipherable by a third party not privy to the communications encrypted using the scheme.
There is, however, a form of encryption referred to as a “one-time pad” which is unbreakable. A one-time pad, as its name implies, is a coding scheme in which a cipher (“pad”) is only used once to encrypt and decrypt a message, and then is discarded and not used again. After the message is sent, a new one-time pad is used for the next message after which it is also discarded, and so forth. Since only one communication is encoded using the particular coding scheme involving a pad, there is no volume of messages encrypted with the same coding scheme on which frequency analysis and other techniques can be used to uncover the underlying code and decipher messages sent using it.
While impregnable in protecting communications from discovery, this form of cryptography has fallen into disuse. This is because of the difficulties involved in generating, disseminating, and protecting the large volume of material required to produce a one-time pad or a series of one-time pads and their underlying keys (a key being a mutually agreed upon “secret” known to both the sender and receiver of a message). One reason for this is that the material generated to serve as a one-time pad or key must have a high degree of randomness which heretofore has not been readily achievable.